Ultragenyx Phase 3 Aspire fails primary and key secondary endpoints in Angelman syndrome

Ultragenyx Pharmaceutical Inc.

• Apazunersen (GTX-102) did not meet primary endpoint (Bayley-4 cognitive raw score change) nor key secondary (MDRI net response).
• No differences vs control on Bayley Cognition raw scores or MDRI mean changes across five individual endpoints.
• Safety profile in Aspire consistent with Phase 1/2; randomized groups comparable at baseline.
• Company will evaluate apazunersen program disposition and implement significant expense reductions while supporting commercial business.